1. Field of the Invention
The present invention relates to operations in a wellbore associated with the production of hydrocarbons. More specifically, the invention relates to a system and method of monitoring and controlling the inflow of a production fluid into a wellbore and/or the injection of fluids into a subterranean formation through the wellbore.
2. Description of the Related Art
Often in the recovery of hydrocarbons from subterranean formations, wellbores are drilled with highly deviated or horizontal portions that extend through a number of separate hydrocarbon-bearing production zones. Each of the separate production zones may have distinct characteristics such as pressure, porosity and water content, which, in some instances, may contribute to undesirable production patterns. For example, if not properly managed, a first production zone with a higher pressure may deplete earlier than a second, adjacent production zone with a lower pressure. Since nearly depleted production zones often produce unwanted water that can impede the recovery of hydrocarbon containing fluids, permitting the first production zone to deplete earlier than the second production zone may inhibit production from the second production zone and impair the overall recovery of hydrocarbons from the wellbore.
One technology that has developed to manage the inflow of fluids from various production zones involves the use of downhole inflow control tools such as inflow control devices (ICDs) and inflow control valves (ICVs). An ICD is a generally passive tool that is provided to increase the resistance to flow at a particular downhole location. For example, a helix type ICD requires fluids flowing into a production tubing to first pass through a helical flow channel within the ICD. Friction associated with flow through the helical flow channel induces a desired flow rate. Similarly, nozzle-type ICDs require fluid to first pass through a tapered passage to induce a desired flow rate, and ICVs generally require fluid to first pass through a flow channel of a size and shape that is adjustable from the surface. Thus, a desired flow distribution along a length of production tubing may be achieved by installing an appropriate number and type of ICDs and ICVs to the production tubing.
One method of monitoring the production patterns of a wellbore involves monitoring the acoustic response to fluid flowing through a wellbore. Some fluid flows, however, do not produce robust or readily identifiable acoustic signals, and thus, it is often difficult to discern whether fluid is flowing through a particular region of the wellbore.